Silencing of Aedes aegypti (Diptera: Culicidae) Doublesex Gene (Dsx) Using iRNAs by Oral Delivery

The Aedes aegypti (Linnaeus 1762) mosquito is the most important vector transmitting dengue virus and other pathogens in Latin America. There are several control programs, many of which are ineffective, and therefore, new control alternatives need to be developed. Small interference RNAs (dsiRNA) are mediators of the interference of gene expression. Silencing RNA is a very conserved mechanism in nature in which small double-stranded siRNA (dsiRNA) regulates gene translation. The aim of this study was to use antisense RNA (dsiRNA and siRNA) by oral administration in stage-I mosquito larvae and evaluate the effect of inhibition of the translation of exon 5 of gene DSX. The exon is removed specifically in males (alternative splicing in exon 5 encodes a protein version of females in dipteran species). The dsiRNA molecule had greater impact on individuals treated, obtaining 25.45% of emerged females, in contrast to the siRNA molecule that had 35.80%, compared with the check in which the emergence ratio was 1:1. This might have been due to the chemical structure of the molecule, because dsiRNA is folded on itself, providing greater stability, compared to single-chain siRNA. Silencing with iRNA of exon 5 in the DSX gene produced changes in sexual differentiation of Ae. aegypti, which could lead to a new mosquito control strategy.